Sunday, October 10, 2021
Bluetooth external Numeric Keypad for contest F-keys
Wednesday, September 22, 2021
MFJ-1026 Noise canceller Modification Plan
After some research on the Internet. I concluded this.
MFJ-1026 Noise Canceller modification Plan
1. Reduce Low frequency attenuation (increase gain at 1.8 MHz)
- Change C8, C16 (680pF) with 1.6nF for Better high pass filtering
- Change C18 (680pF) with 1.6nF for better pass through
- May Change L3, L4, L5, L6 (5.6 uH) with 10 uH ==> No need to change (Just Increase Cap to decrease attenuation at 1.8 Mhz)
2. Better IM Dynamic range
- Remove Diodes D6, D9, D10, D11
3. Better Gain
- Add 4:1 transformer to the output of Q4 (C1)
4. Better control of Phase range (Swap inputs)
- ADD DPDT SW & Coax to swap the inputs of Q8 and Q5
- Q8 -> SW -> R20; Q5 -> SW -> R9
5. Getting Better phase range and control
- Change C13 (120pF) with (47pF => 68pF) - Increased range for high band position
- Change C12 (470pF) with 680pF - Better phase control for low band position
6. Protect Aux Antenna FET from high power operation
- Install an AUX antenna input grounding Relay.
- Connect Relay (+) to (C2-Q1 junction pad) and Relay (-) to (R5-Q2 junction pad), -Install a diode
- Install a protection diode
- Need a 12V relay for isolation and a Diode for protection (NA1S TQ2-12V, Single side stable)
Sunday, February 07, 2021
Setup OpenwebRX for Raspberry pi and RTL-SDR
1. Download Raspberry pi Image from https://www.openwebrx.de/download/rpi.php
2. Burn image to 16GB SD card
3. Install SD card and RTL-SDR into the RPi3B
4. login to local terminal, user/pass = pi/raspberry
5. run "sudo raspi-config" for initial setup
6. setup configuration file for OpenwebRX
cd /etc/openwebrx
sudo nano config_webrx.py
Anaconda, keras install
Go to "Anaconda Prompt"
0. check Conda
conda list # list library
conda update --all # Updates all libraries
conda --version
python --version # --version shows version of the library
1. Create environment
conda create -n py38 python=3.8
conda activate py38 # activate the environment
conda deactivate py38 # deactivate
2. Install keras version
conda install -c anaconda keras-gpu #GPU 버전
conda install -c anaconda keras #CPU 버전
3. Install other packages
conda install -c anaconda pandas # pandas
conda install -c anaconda xlrd
conda install -c anaconda xlwt # excel 파일을 pandas에서 읽고 쓰기
conda install -c anaconda seaborn # 데이터 시각화
conda install -c anaconda scikit-learn # 사이킷런
conda install pillow # 이미지 처리
4. Check at Python/Spyder
import tensorflow as tf
import keras as k
print("Version of Tensorflow = ", tf.__version__)
print("Version of keras = ", k.__version__)